Listen / Telephone

How attentively do we listen to others?
While I was observing a couple of children playing one day, I noticed them playing with a make-believe telephone made of paper cups.
The make-believe telephone is a sensible function that allows people to listen attentively to others. This discovery was adopted as a design motive to propose a telephone design.
One cannot talk and listen at the same time, he/she has to talk after listening to the other party (caller). One can listen to the other party attentively, and give more thought to how to respond to the other party. The phone is designed to be the same size as a paper cup
(6.5 oz).